JPS61111084A - Color image pick-up system - Google Patents

Abstract

PURPOSE:To eliminate the picture-quality degradation caused by an equivalent after-image and to improve the chromatic reproducibility and the chrominance S/N by providing a chrominance coding filter of primary color-mesh that is of mosaic-like formation in front of the solid-state image sensor in order to perform the field reading from all of the photo-receiving parts. CONSTITUTION:During an odd field time, the pick-up output is read out from a solid- state image sensor 10 by means of field-reading. The output is made in a way that the signal charges R and G obtained in each photo-receiving part 11 in an even line L and the signal charges B and G obtained in each photo-receiving part 11 of the odd line L located above in perpendicular from the receiving part 11 of the said even line L, are mixed at a vertical transfer register 12 and read successively via a horizontal transfer register 13. Likewise, in an even field time, the signal charges R and G, and those B and G are mixed at the register 12 and read successively via the horizontal transfer register 13. That is, the image pick-up output read out from the register 13 is such one that the chromatic components of the image information of each picture element of each field are coincident. As a result, a pick-up output correspondent to the interlaced scanning of the NTSC (National Television System Committee) television, is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a charge coupled device (CCD).
The present invention relates to a color imaging method commonly used in solid-state color imaging devices that perform color imaging using a solid-state image sensor formed with a solid-state imaging device such as a Cou-pled Device.

[Conventional technology]

Conventionally, in a solid-state imaging device using a solid-state image sensor formed with a solid-state imaging device such as a COD, in order to obtain an imaging output compatible with interlaced scanning in the standard television system, adjacent images are placed in the vertical direction of the solid-state image sensor. So-called frame readout in which all pixel information of the solid-state image sensor is read out frame by frame by alternately selecting and reading out the image information obtained by the pixels field by field, or by reading out the image information obtained from the pixels in the vertically adjacent pixels. A so-called field readout is performed in which image information of all pixels is alternately selected and mixed for each field, and then image information of all pixels is read out for each field. Furthermore, in a solid-state color imaging device, color imaging is performed using a solid-state image sensor provided with a mosaic-like or striped-like color coding filter on the front surface corresponding to the pixel arrangement.

In solid-state color imaging devices that generally capture color images using a single-chip solid-state image sensor with a small number of pixels,
For example, as shown in FIG. 6, a color coding filter 50 with a primary color arrangement in which green filters CF are arranged in a single pine pattern and a red filter RF and a blue filter BF are provided in the empty spaces has been widely used. There is. In the conventional solid-state color imaging device in which the conventional color coding filter 50 shown in FIG. Since the color components are mixed, the above-mentioned frame readout is performed.

Furthermore, in the conventional solid-state color imaging device that performs color imaging by frame readout as described above, cyan (Cy), cyan (Cy),
Complementary color filters with complementary colors such as yellow (Ye) and magenta (Mg) are used, and for example, cyan color filter cyF, yellow color filter YeF, white color filter WF, and green color filter GF are compatible with the pixel structure of solid-state image sensors. Color coding filters 60 with complementary colors arranged in an array as shown in FIG. 7 are used.

[Problem that the invention seeks to solve]

In solid-state color imaging devices that capture color images using conventional solid-state image sensors equipped with color coding filters in a primary color array, there is a problem in that when field readout is performed, different color components are mixed every other field. I could only read it. In imaging using frame readout, so-called equivalent afterimages occur in principle, making it impossible to perform color imaging with good image quality.Furthermore, color imaging is performed using a solid-state image sensor equipped with a color coding filter in a complementary color array. In solid-state color imaging devices, dyes, etc. that form complementary color filters generally do not have sufficient optical properties, making it impossible to achieve ideal spectral characteristics. However, there were problems in that color reproducibility and color S/N were poor.

Therefore, in view of the above-mentioned conventional problems, the present invention performs color imaging by field readout using a solid-state image sensor provided with a color coding filter in a primary color array, and reproduces color without deterioration of image quality due to equivalent afterimages. It is an object of the present invention to provide a color imaging method that enables color imaging with good color quality and color S/N.

[Means for solving problems]

In order to solve the above-mentioned problems, the color imaging method according to the present invention uses a color coding filter of a primary color array arranged in a mosaic pattern to correspond to the discrete pixel structure of the solid-state image sensor. image information obtained from the solid-state image sensor at each light-receiving section in an even-numbered row of the solid-state image sensor during a first field period, and located adjacent to one side of each light-receiving section in the even-numbered row. The image information obtained from each light receiving section of the even numbered rows of the solid-state image sensor during the second field period is mixed with the image information obtained from each light receiving section of the odd numbered rows and read out sequentially. The image information obtained from each of the odd-numbered light receiving sections located adjacent to the other side of each light receiving section is mixed and sequentially read out, and the color components of the image information of the corresponding pixels of each field match. The present invention is characterized in that the imaging output is read out in the field from all the light receiving sections of the solid-state image sensor.

[Effect]

In the color image method according to the present invention, a color coding filter with a primary color array provided in front of a solid-state image sensor having a discrete pixel structure is used to output an image in which the color components of image information of corresponding pixels of each field match. Field readout is performed from all light-receiving parts of the solid-state image sensor, and imaging output corresponding to a predetermined interlaced scan is obtained, preventing the occurrence of equivalent afterimages as in the case of frame readout, and providing good color reproducibility. Moreover, it enables color imaging with excellent color S/N and brightness signal characteristics.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a solid-state imaging device using a color imaging method according to the present invention will be described in detail below with reference to the drawings.

In the embodiment shown in the block diagram of FIG. 1, the solid-state image sensor 10 is an interline transfer type COD image sensor in which a color coding filter 1 having a primary color arrangement as shown in FIG. The signal charges obtained in each light receiving section 11 are transferred to the vertical transfer register 1.
The data is read out from the horizontal transfer register 13 via 2. The signal charge read out from the solid-state image sensor 10, that is, the imaging output, is supplied to the imaging signal processing circuit 20.

The color coding filter 1 is formed by arranging a red filter RF, a green filter CF, and a blue filter BF in a mosaic shape corresponding to the light receiving section 11, that is, the pixel structure' of the solid-state image sensor 10. A blue filter BF and a green filter CF are alternately and sequentially arranged in the L (2n-1)th row in the horizontal direction, and a green filter G is arranged in an even numbered row L (2n) between them.
F and red filters RF are alternately arranged in the horizontal direction, and the order in which the green filters CF and red filters RF in the even-numbered column L (2n) are alternately repeated in the horizontal direction is reversed for each row. It is an array.

Furthermore, in this embodiment, the solid-state image sensor 1
0 is for the signal charges R, G, and B of each color component obtained from each light receiving section 11 coded by the color coding filter 1 in order to obtain an imaging output compatible with interlaced scanning in the NTSC standard television system. Signal charges R obtained at vertically adjacent light receiving sections 11,
G, B, that is, the image information is transferred to the vertical transfer register 1.
2, alternately and selectively mix every l field, then 1
So-called field readout is performed by reading out the image information of all pixels for each field via the horizontal transfer register 13.

Further, the imaging signal processing circuit 20 processes a luminance signal (Y
) component is extracted from the low-pass filter (LPF) 21;
A process processing circuit 22 performs predetermined process processing on the luminance signal (Y) obtained by each LPF 21, a band pass filter (BPF) 23 extracts the chroma signal (C) component from the image pickup output, and this BPF 23 an IH delay circuit 24 that delays the chroma signal (C) obtained by the BPF 23 by one horizontal scanning period (IH); 1 signal combiner 25 and the BPF 2
The chroma signal (C) obtained in step 3 and the above IH delay circuit 2
A second signal synthesizer 26 that subtracts and synthesizes the delayed outputs of 4.
Then, the luminance signal (Y) is supplied via the process processing circuit 22, and the combined outputs of the first signal synthesizer 25 and the second signal synthesizer 26 are supplied, so that the signal complies with the NTSC system. The encoder 27 forms a color television signal, and forms a color television signal conforming to the NTSC system from the imaging output supplied from the solid-state image sensor 10, and connects the signal output terminal 2 to the signal output terminal 2.
It is configured to output from 8.

In the embodiment configured as described above, during the odd field period, the signal charges R, G obtained at each light receiving section 11 of the even numbered column L (2n) are used as the image pickup output read out from the solid state image sensor 10 in the field. and the even sequence L
The signal charges B and G obtained in each of the light receiving sections 11 of the odd number column L (2n-1) located vertically above each of the light receiving sections 11 of (2n) are transferred to the vertical transfer register 12 as shown in FIG. The signals are mixed as shown and sequentially read out via the horizontal transfer register 13.

In addition, during the even field period, the signal charges R and G obtained in each light receiving unit 11 of the even numbered column L (2n) and the signal charges R and G obtained in each light receiving section 11 of the even numbered column L (2n ) The signal charges B and G obtained from each of the (2n-1) light receiving sections 11 in odd-numbered rows located vertically below each of the light receiving sections 11 are transferred to the vertical transfer register 12 at the fourth [! ! Mixed as shown in Q,
The data are sequentially read out via the horizontal transfer register 13.

That is, in this embodiment, the image pickup output in which the signal charge, that is, the image information obtained by all the light receiving sections 11 of the solid-state image sensor 10 for each field is read out from the horizontal transfer register 13 via the vertical transfer register 12 is as follows. The color components of the image information of each pixel in each field match, and by reading out the field using the color coding filter 1 with a primary color arrangement, it is possible to obtain an imaging output compatible with interlaced scanning in the NTSC television system. can. As in this embodiment, if field readout is performed using a color coding filter l with a primary color arrangement, color reproducibility is better than when using a color coding filter l with a complementary color arrangement, and the color S /N
It is possible to perform color imaging with excellent brightness and brightness signal characteristics. Moreover, in this embodiment, since field readout is performed, equivalent afterimages do not occur as in the case of frame readout (and color imaging with extremely good image quality can be performed).

Note that the color imaging method according to the present invention is not limited to the above-described embodiment, and the arrangement of the red filter RF and the blue filter BF of the color coding filter 1 in the above embodiment may be switched, for example, as shown in FIG. Even if a color coding filter 2 having a primary color arrangement as shown in FIG.

In addition, solid-state image sensors are not limited to the above-mentioned interline transfer type CCD, but also frame transfer type COD and BBD (Bucket Bri-
gade Device L M OS (Metal
It is also possible to use a solid-state image sensor formed of oxide sen+conductor) or the like.

〔Effect of the invention〕

As is clear from the description of the embodiments described above, in the color imaging method according to the present invention, field readout is performed using a color coding filter with an array of primary colors to obtain an imaging output corresponding to a predetermined interlaced scanning, so that frame readout is It is possible to perform color imaging with extremely good image quality without producing equivalent afterimages as in the case of conventional methods, and the color reproducibility is better than when using a color coding filter with a complementary color array. Color imaging with excellent S/N and brightness signal characteristics can be performed, and the intended purpose can be fully achieved.

[Brief explanation of drawings]

Figure 2 is a block diagram showing an embodiment of a solid-state color imaging device using the color imaging method according to the present invention;
The figure is a schematic diagram schematically showing the structure of the color coding filter used in the above embodiment, and FIG. 3 is a schematic diagram schematically showing the readout state of the imaging output during the odd field period in the above embodiment. , FIG. 4 is a schematic diagram schematically showing the readout state of the imaging output during the even field period in the above embodiment. FIG. 5 is a schematic diagram schematically showing another example of a color coding filter having a primary color array that is used in the color imaging system according to the present invention. Figure 6 is a schematic diagram showing the structure of a conventional primary color array color coding filter commonly used in solid-state color imaging devices. FIG. 1 is a schematic diagram schematically showing the structure of a conventional complementary color array color coding filter. 1.2...Color coding filter 10...Solid image sensor 11...Light receiving section 12...Vertical transfer register 13 ... Horizontal transfer register 20 ... Imaging signal processing circuit

Claims (1)

[Claims] A color coding filter having an array of primary colors arranged in a mosaic pattern corresponding to the discrete pixel structure of the solid-state image sensor is provided in front of the solid-state image sensor, and the color coding filter is provided in front of the solid-state image sensor in a first field period. The image information obtained by each light receiving section in an even numbered row of the image sensor is mixed with the image information obtained by each light receiving section in an odd numbered row located adjacent to one side of each light receiving section in the even numbered row, and the image information is sequentially mixed. image information read out and obtained by each light receiving section in an even numbered column of the solid-state image sensor during the second field period and each light receiving section in an odd numbered column located adjacent to the other side of each light receiving section in the even numbered column. The image information obtained in the solid-state image sensor is mixed and sequentially read out, and the image output in which the color components of the image information of the corresponding pixels of each field match is field read out from all the light receiving parts of the solid-state image sensor. A color imaging method featuring